How can I fix the recovery mode on my One?

Hello everyone! I am in the process of rooting my HTC One, but I have hit a snag. I have followed through with the Bootloader Unlock process found on HTC Dev, but cannot take the next step - booting into recovery.

For some reason, every recovery I try to flash (using fastboot flash recovery recovery.img) including CWM and TWRP wont boot. it simply shows the 'booting recovery...', and then shuts down to a black screen. Any ideas?